Diesel hammer for pile drivers



April 3, 1962 A. LANG ETAL DIESEL HAMMER FOR FILE DRIVERS 2 Sheets-Sheet 1 Filed Feb. 6, 1958 5 z M g r a M W 7 w; 3 M 0 1% a 418 FIG.1

A h n n n n w u w w A 1 A f 4 1M 1 X 4/ AM 3 i 3 i u Iii u H. .HHHWWWWWHHH m\ mmx a l f J m m mm mi m m m m m Mir April 3, 1962 A. LANG ETAL DIESEL HAW/[ER FOR FILE DRIVER'S 2 Sheets-Sheet 2 Filed Feb. 6, 1958 IDA/P140 #4465 J United States Patent 3,027,883 DIESEL HAMMER FOR PILE DRIVERS Anton Lang, Hartberg, Austria, and Alfred Glehr, Hasenreinweg, Esslingen (Neckar), and Konrad Haage, Esslingen, Germany, assignors to Delmag Maschmenfabrik Reinhold Dornfeld, Esslingen (Neckar), Germany Filed Feb. 6, 1958, Ser. No. 713,597 Claims priority, application Germany Feb. 8, 1957 4 Claims. (Cl. 123-7) The present invention relates to pile drivers and, more particularly, refers to a diesel hammer for pile drivers, which includes a piston and an air-cooled cylinder. Such diesel hammers are either air-cooled or evaporation cooled. Generally, especially with light weight hammers, the cooling by the outer air in connection with cooling fins sufl-lces inasmuch as between the driving-in of one pole and the driving-in of the next pole sufficiently long intervals prevail during which the hammer does not work. These intervals are necessary in order to be able to move the hammer from one pole to the place where the next pole is to be driven into the ground, and also for erecting the new pole and placing the hammer thereupon.

However, when very heavy driving operations are involved during which the hammer beats down upon one and the same pole for hours without any interruption, the cylinder may be subjected to temperatures which are hardly permissible.

It is, therefore, an object of the present invention to provide a diesel hammer in which, even under the last mentioned circumstances, air-cooling will sufliee so that evaporation cooling will be avoided.

It is another object of this invention to provide a diesel hammer which will make it possible, even when operat ing the hammer for a long time without interruption, to bring about a particularly effective cooling of the cylinder head and also of the piston.

These and other objects and advantages of the invention will appear more clearly from the following specification in connection with the accompanying drawing in which FIG. 1 diagrammatically illustrates a longitudinal section through a diesel hammer according to the present invention.

FIGS. 2 and 3 respectively illustrate two longitudinal sections through two modified diesel hammers of the present invention.

The diesel hammer according to the present invention is characterized primarily in that within the wall of the cylinder and also in the piston or, if desired, only in one of the last mentioned two parts, a passage system is so arranged and in communication with the cylinder chamber and the outside air that that side of the piston which is not required for scavenging purposes will during its relative reciprocation with regard to the cylinder feed cold air close to the combustion chamber of the cylinder. According to a particularly advantageous feature of the present invention, the passage system contains a reduced cross section within the range of those portions which are to be cooled especially efiectively. Such portions are for instance the cylinder head and also the piston. This reduction in the effective cross section of the passage system may be brought about for instance by providing the cylinder head inserted in the upper end portion of the cylinder with narrow circumferential grooves. These grooves should communicate on one hand with the outside air and on the other hand with the lower end of the cylinder chamber.

It is particularly advantageous to design the piston head in such a way that its length is less than the relative working stroke so that during the downward movement of the freely dropping cylinder, the exhaust slots will for 3,027,883 Patented Apr. 3, 1962 some time be below the lower edge of the piston head so that cold air will be drawn in against the lower side of the piston head.

The drawing illustrates a diesel hammer in which the upper surface of the stepped or differential piston will, following the exhaust, act as scavenging pump, and, in a manner known per se, will draw fresh air into the cylinder through the upwardly inclined exhaust slots. It is, however, to be noted that the invention can also be materialized in connection with such differential pistons in which the lower side of the piston step arranged in the central portion of the piston rod, will act as scavenging pump. In such an instance, the respective side which is remote from said scavenging pump side of the piston step will then be employed for the pumping of the cooling air in conformity with the invention.

Referring now to FIG. 1 of the drawing in greater detail, the cylinder 11 effecting the driving action is provided with cooling fins 111 and comprises a cylinder bore 119 in which a drum type or ditferential piston is arranged which has two oppositely located effective areas. This piston comprises a piston head 121 and a piston rod 122 which latter is guided in the lower end of the cylinder 11. The drawing shows the cylinder in its lower dead center position. The cylinder head is furthermore provided with a recess 123 forming a combustion chamber, and also with piston rings 19. Mounted upon the cylinder 11 is a fuel tank or reservoir 13, while between the said fuel tank 13 and the upper portion of the cylinder bore there is arranged a fuel pump generally designated 15. This fuel pump may be of any standard design.

The piston 15a of the fuel pump is guided in the cylinder head 16 and rests upon the latter through the intervention of a spring 17. Fuel from the tank 13 passes through passages 161 into the injection nozzle 162 from whereby means of the lowermost end of the pump piston 15a it it is injected into the combustion chamber 123.

The circumference of the cylinder head 16 is provided with circular grooves 163 which are relatively narrow. The said grooves 163 are arranged within the broadened portion 112 of a passage or conduit 113 provided within the wall of the cylinder 11. As will be evident from the drawing, the lower end of said conduit 113 leads into the lower portion of the cylinder bore 119, whereas the broadened portion 112 of said passage 113 communicates with the outside air. The cylinder 11 furthermore comprises an exhaust passage 114, which simultaneously acts as scavenging passage.

The relative stroke of the piston head 121 with regard to the cylinder 11 from its relative upper dead center position up to the point where the scavenging passage 114 is released, is designated with the letter h while the total relative piston stroke is designated with the letter k and the height of the piston head 121 is designated with the letter h When due to the explosion of the combustion gases, the cylinder 11 is thrown upwardly, the differential piston 121, 122 remains seated on the pole 18 due to the weight of said piston and the explosion pressure acting thereupon so that the upper piston side in a manner known per so will through the scavenging slots 114 draw into the cylinder a quantity of air equaling a multiple of the relative piston displacement whereby the cylinder will be scavenged. At the same time, the air in that portion of the cylinder which is below the piston head 121 will through the passage 113 including the enlargement 112 and the annular grooves 163 be exhausted to the outside. Inasmuch as the annular grooves 163 with the enlargement 112 represent a restriction relative to the cross section of the passage 113, it will be evident that the gases passing through the said grooves will within the range of the cylinder head reach a particularly high speed and will thereby bring about a good cooling effect in that portion where normally the highest temperatures occur. The expansion stroke of the combustion gases corresponds to the distance h whereas the exhaust stroke for the cooling air corresponds to the distance h h should possibly be a multiple of h. If the cylinder 11 is thrown upwardly by a distance greater than 12 also the piston 121, 122 is carried upwardly due to the air cushion formed below its piston head 121.

When the cylinder 11 again drops, piston 121, 122 will again draw in cold air through the passages 113 and 163 as soon as the piston again rests upon the pole 18. The drawn-in cold air will then be exhausted in the above mentioned manner when the cylinder 11 is again thrown upwardly. Inasmuch as the air passages 163 are arranged within the range of the hottest portion of the cylinder, the above mentioned rhythmic drawing-in and exhaustion of the cold air adds a particularly strong cooling effect to the outer air cooling of the entire hammer. Furthermore, the height h;; of the piston head 121 may be designed shorter than the working stroke portion h so that cold air will through the upwardly inclined exhaust slots 114 still pass against the lower side of the piston head 121 thereby additionally cooling the same before the cylinder 11 hits the pole 18.

The piston 121, 122 is furthermore provided with a longitudinal bore 125 of relatively large cross section. This bore branches out into a plurality of narrow branch passages 124 in the piston head 121, which branch passages first extend in radial direction and then downwardly to the lower side of the piston head. At the lower end of the piston rod, transverse passages 126 are provided, which communicate with the bore 125 and are controlled by the bottom edge of the cylinder bore 119. During the relative downward stroke of the piston 121, 122 in the cylinder bore 119, the air in the bore 119 will, after the piston has moved beyond slot 114, be exhausted to the outside also through the passages 124, 125. Conversely during the stroke in the other direction, the air will be drawn in as cool fresh air during which step the piston head 121 will be cooled particularly intensely.

The arrangement of FIG. 2 differs from that of FIG. 1 in that the passage 113 of FIG. 1 has been omitted in FIG. 2.

The arrangement of FIG. 3 differs from that of FIG. 1 in that the passage 125 of FIG. 1 has been omitted in FIG. 3.

The operation of the devices of FIGS. 2 and 3 will be obvious from the description of the operation of FIG. 1.

It is, of course, to be understood that the present invention is, by no means, limited to the particular construction shown in the drawing but also comprises any modifications within the scope of the appended claims.

What we claim is:

1. In combination in a diesel hammer for a pile driver, which includes an air scavenged cylinder piston system: a first member forming the cylinder of said cylinder piston system and comprising a cylinder bore, a second member in form of a piston having two different oppositely arranged effective areas and forming the piston of said cylinder piston system, said piston being arranged within said cylinder bore for relative movement thereto, a cylinder head connected to said cylinder and confining with the latter and one of said efiective piston areas a combustion chamber, a piston rod connected to the other one of said effective piston areas and extending through said cylinder bore in spaced relationship thereto in the direction away from said cylinder head so as to confine with said cylinder bore an annular chamber, said cylinder head having circular grooves therearound so as to form fins around said cylinder head, first passage means establishing communication between said grooves and the atmosphere, second passage means leading from said annular chamber at a point thereof remote from said cylinder head to said grooves for conveying cooling air thereto,

said cylinder bore being closed at its end remote from said cylinder head, and third passage means arranged in said cylinder and spaced from said cylinder head by a distance exceeding the height of said piston, said third pas= sage means establishing communication between said an= nular chamber and the atmosphere for conveying scav' enging air into said annular chamber and for exhausting exhaust gases from said annular chamber, said one of said effective piston areas forming the scavenging piston surface for the scavenging air in said cylinder bore between said one effective piston surface and said cylinder head, and the other one of said effective piston areas forming the pumping surface for the cooling air and being operable to convey the cooling air into the neighborhood of the walls of said combustion chamber.

2. A diesel hammer according to claim 1, in which said piston is provided with passages therein communicating with said annular chamber, and in which said piston rod is provided with a longitudinal bore communicating with the passages in said piston and is also provided with transverse passages for communication with said annular chamber when said piston is in a position between said third passage means and said cylinder head. I I

3. In combination in a diesel hammer for a pile driver, which includes an air scavenged cylinderpiston systemt a first member forming the cylinder of said cylinder piston system and comprising a cylinder bore, a second member in form of a piston having two different oppositely ar ranged effective areas and forming the piston of said cylin= der piston system, said piston being arranged within said cylinder bore for relative movement thereto, a cylinder head connected to said cylinder and confining with the latter and one of said effective piston areas a combustion chamber, a piston rod connected to the other one of said effective piston areas and extending through said cyl inder bore in spaced relationship thereto in the direction away from said cylinder head so as to confine with said cylinder bore an annular chamber, said cylinder head having circular grooves therearound so as to formfins around said cylinder head, first passage means establishing communication between said grooves and the atmosphere, second passage means leading from said annular chamber at a point remote from said cylinder head to said grooves for conveying cooling air thereto, said cylinder bore be ing closed at its end remote from said cylinder head, and third passage means arranged in said cylinder, said third passage means establishing communication between said annular chamber and the atmosphere for conveying scavenging air into said annular chamber and for exhausting exhaust gases from said annular chamber, said one of said effective piston areas forming the scavenging piston surface for the scavenging air in said cylinder bore between said one effective piston surface and said cylinder head, and the other one of said effective piston areas forming the pumping surface for the cooling air and being operable to convey the cooling air into the neighborhood of the walls of said combustion chamber.

4. In combination in a diesel hammer for a pile driver',

I which includes an air scavenged cylinder piston system:

a first member forming the cylinder of said cylinder piston system and comprising a cylinder bore, a second member in form of a piston having two different oppositely arranged effective areas and forming the piston of said cylinder piston system, said piston being arranged within said cylinder bore for relative movement thereto, a cylinder head connected to said cylinder and confining with the latter and one of said efiective piston areas a combustion chamber, a piston rod connected to the other one of said effective piston areas and extending through said cylinder bore in spaced relationship thereto in the direction away from said cylinder head so as to confinewith said cylinder bore an annular chamber, said piston being provided with passages therein communicating with said annular chamber, and said piston rod being provided sages in said piston and being further provided with transverse passage means communicating with said longitudinal bore and located in that end portion of said piston rod which is vremote from said piston for communicating with the atmosphere during a considerable portion of the stroke 5 of said cylinder relative to said piston, said cylinder bore being closed at its end remote from said cylinder head, and passage means establishing communication between said annular chamber and the atmosphere for conveying scavenging air into said annular chamber and for exhausting exhaust gases from said annular chamber, said one of said eifective piston areas forming the scavenging piston surface for the scavenging air in said cylinder bore between said one efiective piston surface and said cylin-' der head, and the other one of said efiective piston areas forming the pumping surface for the cooling air.

References Cited in the file of this patent UNITED STATES PATENTS 1,328,685 Palmer Jan. 20, 1920 2,128,584 Haage Aug. 30, 1938 2,140,205 Haage Dec. 13, 1938 10 2,305,772 Haage Dec. 22, 1942 FOREIGN PATENTS 884,928 Germany M July 30, 1953 

